docs: fix import in response manipulation example (#10503)

# Which Problems Are Solved

Fixes one of the two issues mentioned in:
https://github.com/zitadel/zitadel/issues/10502

The response manipulation example has the wrong import in the Golang
code.

https://zitadel.com/docs/guides/integrate/actions/testing-response-manipulation

# How the Problems Are Solved

Changes the example document to use the right import address.

# Additional Changes

None.

# Additional Context

Replace this example with links to related issues, discussions, discord
threads, or other sources with more context.
Use the Closing #issue syntax for issues that are resolved with this PR.
- Partially resolves #10502
- https://discord.com/channels/927474939156643850/1405813424901984380

docs/docs/guides/integrate/actions/testing-request-manipulation.md

@@ -41,7 +41,7 @@ import (
 	"io"
 	"net/http"
 
-	"github.com/zitadel/zitadel/pkg/grpc/user/v2"
+	"github.com/zitadel/zitadel-go/v3/pkg/client/zitadel/user/v2"
 	"google.golang.org/protobuf/encoding/protojson"
 )
 

docs/docs/guides/integrate/actions/testing-response-manipulation.md

@@ -41,7 +41,7 @@ import (
 	"io"
 	"net/http"
 
-	"github.com/zitadel/zitadel/pkg/grpc/user/v2"
+	"github.com/zitadel/zitadel-go/v3/pkg/client/zitadel/user/v2"
 	"google.golang.org/protobuf/encoding/protojson"
 )